1. The Field Of The Invention
This invention relates to conveyor lubricators and more particularly to an automatic conveyor lubricator that deposits a predetermined quantity of oil on each part to be lubricated and provides an air assist for conveying the oil to the part.
2. Description Of The Prior Art
An overhead conveyor mechanism typically comprises a series of wheeled trolleys that ride along a fixed track following a predetermined path, with the trolleys being interconnected by a chain formed of a number of interconnected solid links. There are a number of moving parts in the conveyor assembly itself, principally, the wheels on the trolleys and the pins interconnecting the links of the chain. All of these parts require periodic lubrication.
These parts can be lubricated by hand, but this is a time consuming and laborious process, and the frequency with which lubrication is required makes lubrication by hand an expensive undertaking. Also, lubrication by hand is an imprecise method of lubricating a part and often causes the deposit of too much lubrication on the moving parts. This excess lubrication can drip from the conveyor, and with an overhead conveyor, such dripping can fall onto the part being conveyed by the conveyor. If the part is being conveyed for a painting or other finishing operation, the presence of oil on the part can cause the part to be rejected. Thus, it is desirable to lubricate each part at regular intervals and precisely enough to provide just enough lubrication for the moving components of the conveyor.
A number of automatic lubricating devices have been devised for conveyor assemblies, with most lubricating devices being designed specifically for overhead conveyors, where excess lubrication drippage is most undesirable. These devices have included apparatus for applying grease to lubrication fittings on the part and to oiling devices for supplying oil to exposed components of the assembly.
Several different types of devices have been employed for applying oil to conveyor linkages. One type is simply a mechanical pumping device that discharges a quantity of oil from a nozzle onto a component of the conveyor whenever the mechanism is actuated by a trolley tripping an appropriate actuating valve. The problem with a purely mechanical lubricating device is that it is difficult to position the nozzle close enough to the part to insure that the oil is deposited directly on the part to be lubricated. Also, because of the surface tension of the oil, a portion of the oil tends to remain as a droplet on the end of the outlet nozzle. This oil collects dirt and dust and may fall at a later time onto a part conveyed by the conveyor.
Another type of oil lubricating device is called a spray or mist type of lubricator. In this type of system a jet of air is directed on the part to be lubricated and a Venturi device in the conduit conveying the air to the part is employed to draw oil into the stream of air being blown against the part. The result of this type of device is that oil is generally sprayed as a fine mist all over the part and is not conveyed with any accuracy to the particular location needing lubrication. This spray also can settle on the parts passing below the lubricator, causing rejection of the parts. Also, the inaccuracy of the spray prevents the complete lubrication of the part and thus requires additional and excessive lubrication in order to properly lubricate the part. The additional lubrication necessary causes additional deposits of oil on the parts.
Another way of lubricating conveyor chains is to apply lubrication to the chain with a brush or other similar applicator dipped in oil and having the brush engage the conveyor chain as it passes. They type of apparatus also results in inaccurate lubrication of the parts and a deposit of excess oil on the conveyor assembly.
Another disadvantage with prior art conveyor lubricators that contributes to the problem of oil dripping on the parts carried beneath the conveyor is that these lubricators are not capable of depositing a sufficiently small amount of lubrication on each part requiring lubrication. Rather, the prior art lubricators are somewhat crude and deposit substantially greater quantities of oil than are required.